At long last, it feels as if fashion has begun opening up to plus-size women. Last year, amazing new plus-specific brands like Premme and All67 launched alongside exciting additions from high-end favorites like Universal Standard and Gwynnie Bee. In 2018, the theme is all about expansion, as companies that previously only served sizes up to XL are making inroads into the plus-size fashion business. Already this year, J.Crew and sister company Madewell, Wildfang, and Ann Taylor LOFT have extended their size ranges, while Target’s just-dropped Universal Thread line offers pieces all the way from the lower end of the sizing spectrum to well into the 20s. With a robust push into extended sizing, it’s an exciting time for plus-size shoppers. But just because it’s being done, doesn’t mean it’s being done right.

One problem is that the traditional way designers create clothing in different sizes isn’t as effective at the upper ranges. To determine the size and cuts of their garments, fashion brands measure against fit models, who typically represent standard sizes—they’re “straight models,” the term for non-plus models. It’s kind of like using a live mannequin to mold a garment; once a brand has the pattern figured out, the measurements are multiplied to fit different sizes using a formula. But this sizing-up method doesn’t account for common disparities between straight and curvy body shapes. And, not surprisingly, plus-size shoppers can tell the difference in the cuts.

“Many brands just scale up straight-size fit model sizing, which doesn't work as the scale in plus sizes has greater variance,” says Alexis Krase, who buys merchandise for her Williamsburg, Brooklyn, boutique Plus BKLYN, which she opened in response to the lack of hip, well-fitting clothing in her size. “I've seen this happen with a number of brands whose clothing ends up running super small; it can prove really frustrating when a 3X fits more like a US 1X.”

Recognizing that simply multiplying up from a standard size doesn’t always work, LOFT redesigned a couple of their existing sizes based on plus-size fit models. Before launching the new plus line, LOFT already carried clothing in sizes 16 and 18 based off the measurements of a straight-size fit model, according to a company spokesperson. The new collection includes 16W and 18W, which are based off a separate plus-size fit model.

Cece Olisa, a blogger working with LOFT to launch its recent expansion and co-founder of annual NYC-based plus fashion event The Curvy Con, which creates a place where plus-size women can shop their favorite online brands, notes that while differences between brands’ marked sizes and exact fit occur to some extent across the board, the wider diversity in body shapes represented above most mainstream retailers’ sizing thresholds makes things even more complicated.

Olisa’s proportions aren’t necessarily close to those of a brand’s chosen straight-size fit model, so she worries about these discrepancies when she shops. "My waist is significantly narrower than my hips,” she says, “but I carry weight in my tummy.” She regularly reviews different brands on her YouTube channel, and depending on a specific garment’s cut and fabric, wears anywhere from a size 18 to a 22.

There’s also the major issue that brands often top out at a tag size 24 or 26—a demarcation that places Krase on an awkward cusp at many stores, or sizes her out entirely. Unfortunately, there’s a major drop-off of clothing options at that point. For example, a quick search on ShopStyle for black dresses brings back 70.6K options in size S/2-4, 479 in size 2X/18-20, and only 71 in 5X/30-32.

Each of the recently launched plus lines or expansions varies both in its range of tag sizes, and in said sizes’ corresponding measurements and proportions. Universal Thread ranges from a 00 to a 26, which is also LOFT’s new largest number size. Wildfang’s suit separates (a notoriously hard-to-fit style) goes up to a 22. Madewell’s modest selection of extended size jeans runs to a 20, according to tag sizes—though as Revelist pointed out, its measurements seem to correspond more closely to a 14 or 16.

So, it’s complicated. Adding larger sizes doesn’t necessarily mean that brands’ new garments will actually fit all their target customers. Between ranges that don’t go high enough and a lack of standardization in sizing, many larger-bodied women are still feeling left out.

What’s more, Olisa laments the way that brands seem to lose touch with their core styles when introducing plus-size pieces.

“I’m likely to check out a newly extended range because all I've ever wanted was options,” she tells SELF. “But often when designers branch into plus, the clothes have a completely different aesthetic than what they’re known for. It’s frustrating if you've watched a brand for a long time, and when their clothes finally come in your size, they’re nothing like what you fell in love with. “

Though she’s happy to see more brands branching out, she’s loyal to those that have always been loyal to her demographic. “I'm always willing to give a newly extended line a chance,” says Olisa. “If brands are starting to pay attention and serve me, I have to let them know they're doing the right thing, and I do that with my dollars. That said, I still have stores that I go to for certain things no matter what.”

Krase concurs. While she’s excited about and supportive of the recent shifts in retail, she does have a few reservations. “I tend to trust designers more who focus solely on plus, since the straight-size inclusive world has yet to really nail plus sizes,” she says. “I also think plus-size bodies have been marginalized in fashion for so long that I'd be more cautious about purchasing from brands that have not historically been open to clothing plus-size customers in the past.”

Both Olisa and Krase agree that many brands newly catering to plus-size audiences have a long way to go until they're on par with pioneering plus brands like Lane Bryant.

“Public exposure to plus-size women in media, in fashion, and in runway shows is helpful, but there’s still a ton of progress that needs to be made,” Krase says.